The problem:

Cancer sucks.  A natural phenomenon that helps protect us from cancer in space is magnetism, which for us comes in the form of Earth’s magnetosphere.  Earth has a magnetosphere because of the liquid iron outer core, and the iron’s movement within the core.  Helping amplify the effect is the rotation of the Earth in what is called the Coriolis force.

What does this mean?

A picture of bubbles in and out of focus in what appears to be a backyard.
Pack it up, we’re moving to the next bubble.

Well, it means outside of Earth’s protection, there isn’t much natural help when Man moves from planet to planet.  Before even considering those other planets, we have to think about the vast expanses beyond our starting and ending protective bubbles (if the destination even has one set up yet).  In these vast expanses, we will be lacking a magnetosphere.


29.58 Eiffel Towers worth of material would be needed to allow safe passage through space.

What if we brought a magnetosphere with us?

We have some rough knowledge of the size of the mechanisms for Earth’s magnetosphere.  The inner core is roughly 70% the size of the moon, or at about 18.9% the size of the earth.  The magnetosphere head that is produced is about 10 Earth radii upwind, with the downwind tail being larger1.

How much of this stuff would we need?

The ISS is about the length of a football field.  People habitat quite well on the ISS, and with a design change towards a sphere, more people can live well, too.  To be able to have a magnetic field protect our space explorers, we need to use some math.  18.9% of a football field is 20.601 meters.  That is our inner core diameter.  The Earth’s outer core is 2,300 kilometers thick compared to the inner core’s radius of 1,220 kilometers.  With that comparison, an outer core would need to be 38.838 meters thick to match our inner core at 20.601 meters.   That is a volume of 879,636 cubic meters.  With iron weighing 491 pounds per cubic meter, we’re talking about 431,901,276 (215,950.638 tons) pounds of iron2.  The Eiffel Tower, for comparison, used 7,300 tons of iron.  29.58 Eiffel Towers would be needed to allow safe passage through space.

At a price of $58.31 per ton, our iron core will cost US$12,592,102.813.

Follow this series as we try to build a spaceship that helps Man extend further into space.  Until then, check out these future spacecraft:

Thanks for stopping by,



A MEETING WITH THE UNIVERSE  Chapter 3-4  The Magnetosphere: Our Shield in Space. Accessed February 25, 2017.
Density of metals. Accessed February 25, 2017.
Iron Ore Fines Prices and Iron Ore Fines Price Charts – InvestmentMine . Accessed February 27, 2017.




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